1. Field of the Invention
The invention relates to a preferably electrically driven single-drive-axis vehicle, which may be referred to as a single-axle vehicle, with a platform and/or a seat for a driver.
2. Discussion of the Background
Such vehicles are known by the term scooter or personal transporter and are, for example, commercially available from the company Segway Inc., Bedford, N.H., USA, and presented in U.S. D528,486. In these vehicles, two wheels are arranged to the right and left of a footboard and can be respectively driven by a brushless electric motor in the wheel hubs.
During normal use, the footboard is in this case located under the axis of rotation of the wheels. Arranged under the footboard is a storage battery pack, by means of which the wheel-hub motors are supplied with electrical energy. Also provided is a control column with a handle, for example similar to the handlebars of a bicycle, the control column being pivotably mounted to a certain extent. The axis about which the control column with the handlebars can be pivoted in this case points in the direction of travel. The wheel-hub motors are activated by means of a regulating system with a number of gyroscopes and acceleration sensors.
Changes in the position of the centre of gravity are detected by the regulating system and corrected by suitable activation of the motors. This ensures that, when such a vehicle is operated, the unsteady equilibrium is maintained. Travel is controlled by appropriate weight displacement to the front or the rear. Such a vehicle is steered by moving the control column out to the sides. In accordance with the extent to which it is moved out, the rotational speeds of the motors on the right and left are changed, so that the desired radius of curve is obtained. Turning on the spot is likewise possible by activating one wheel in the forward direction and one wheel in the reverse direction.
Commercially available embodiments of such single-axle vehicles require a base area of less than 0.5 m2, have a weight of the order of 50 kg together with a maximum speed of approximately 20 km/h and a range of 20 to 40 km on one battery charge. NiMh batteries or lithium-ion batteries are usually used as the storage batteries.
WO 2006/042302 A1 describes details of a controlling and position-regulating system with which a four-wheel, electrically operated vehicle for transporting one person can also be operated stably on only two wheels of one axle, if for example the front axle is raised. To this extent, such a vehicle is operated as a single-axle vehicle in the way described at the beginning.
Small electrically operated vehicles for transporting a single person are commonly used where relatively long distances have to be covered, considered on the one hand to be too far to cover on foot and on the other hand too short to justify the use of a motor car. Such vehicles are also used in locations that cannot be accessed by larger vehicles, or where cycles are traditionally used. Worksites or extensive building complexes are concerned for example. Furthermore, electrically driven vehicles are particularly used by elderly or disabled people, to enable them to get around further away from where they live.
In a similar way, small vehicles are also known for various work to be performed on correspondingly extensive properties or estates, for example for cleaning in buildings or areas of estates, or for example ride-on lawnmowers for mowing extensive areas of grass.
For people who already use a small electrically operated vehicle, for example elderly people, it has also been proposed to fit such an already existing vehicle with an attachment to reduce the investment outlay. An example of such a small electrically operated vehicle with an attachment formed as a lawnmower is described, for example, in US 2006/0090441 A1.
Another attachment, known for example from EP 1 180 342 A1, links small vehicles driven by muscle power, in this case a scooter with a front pair of steerable wheels of adequate track width, with an attachment to allow certain work to be performed more easily and quickly over large areas. In the case of the example described there, the attachment is a kind of wiping mop, to allow large interior areas to be cleaned quickly and efficiently, for example the walkways in a shopping centre. Particular advantages in the case of such a solution are the low weight, the low outlay required, the constant availability and the elimination of operating costs, apart from possibly required repairs.
However, the use of such vehicles is only possible on relatively smooth surfaces that allow low rolling and pushing resistance, so that the latter can be overcome relatively easily by the user.
None of the known solutions provides the possibility of making work easier in areas that present resistances to movement too great for muscle-powered vehicles but are so small or full of corners that four-wheeled electric carts with attachments do not represent a viable alternative to self-propelled machines, such as ride-on mowers.